I have a bottle of FeCI from RatShack I bought 15 years or more
ago still unopened. Read all kinds of stories about that stuff.
Being I am a noob just starting I read all the comments and I may
try different methods so this is just another note in my toolbox.
Thanks
On 3/23/2019 4:29 PM, dale.chatham
wrote:
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I hafe to add my experience with aerating etching solutions.?
I had a tank using ammonium persulfate.? I etched in a closet in
my carport.? After a dozen or so, i looked and the heads of all
the nails were missing.? Aerosolizing etchant is not a good idea
and it can grt anywhere.? I use HCl + H2O2 + H20.? Ru;er gloves,
rubbing the boards and 5 to 10 minutes later im done.? It takes
me less than 1/4 cup of etchant to do a board.? HCl is cheap at
Lowe's and 35% H2O2 is readily available from Amazon.
I never liked FeCl.? Too thick and the sludge buildup kept
the etchant away from the board.
I woufd suggest a water pump over aeration.? I have also seen
bubbles protect the copper from the etchant.
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-------- Original message --------
Date: 3/23/19 2:08 PM (GMT-06:00)
Subject: Re: [homebrewpcbs] Bubble Tank DIY Plans
On Sat, 23 Mar 2019 14:33:48 -0400, you wrote:
>High concentrations of H2O2 result in VERY exothermic
reactions. Etching takes place in seconds. Lots of heat. Lots of
acrid fumes. Do outside or with a good hood. Have water available
to put your board in to stop the etching. I did a lot with those
high mixtures but decided it wasn't worth the problems and went
back to 3% peroxide. I usually use a sponge with a small quantity
of etchant. Takes a minute or two but is very controllable and
uses only a fraction of the volume, making disposal much easier. I
don't make a lot of boards, so it's not worth keeping vats of
chemicals around.
The "top up the solution" is meant to add enough H2O2 to restore
the
solution to good operation, but NOT to replace a lot of water.?
You
want to maintain the overall concentration.? The goal (I think) is
to
maintain the same concentration you get with 3%, but not end up
diluting the overall mixture.? You do lose some to evaporation,
etc.
Harvey
>
>
>Mark
>
>
>At 12:32 PM 3/23/2019, you wrote:
>Noted.
>
>
>Thanks,
>
>
>Dave
>
>
>On 3/22/2019 7:40 PM, Harvey White wrote:
>On Fri, 22 Mar 2019 20:31:31 -0400, you wrote:
>
>
>I found Sally Beauty Supply to be a good source for H2O2. I
recall the
>"volume" rating is a bit more than 3x the concentration, so
"30 Volume"
>H2O2 is 10% concentration.Do be careful, since the drugstore
concentration is far less than the
>various products available in beauty supply stores.
>
>
>I'd think that the best use is as follows:
>
>
>1) build the etchant with drugstore H2O2 and HCL.
>
>
>2) when desired, top up the mixture with beauty supply H2O2,
but in
>far less quantity than needed for the initial mixture.
>
>
>YMMV
>
>
>
>
>Harvey
